Modern meat processing facilities employ special practices and equipment to help ensure that the meat being processed does not become contaminated with pathogenic bacteria such as certain strains of E. Coli, Salmonella, and Staph bacteria, for example. However, even with careful handling, meat products are almost inevitably exposed to pathogenic microbes in the course of processing. Furthermore, nonpathogenic bacteria are also inevitably present in the meat being processed and propagate as part of the natural decay process of the meat. Meat processing facilities chill meat quickly after slaughter to help reduce the growth rate of all types of bacteria in the meat product and to slow the natural decay processes in the meat. However, simply chilling meat does not kill most types of bacteria that may be present in meat, and allows many types of microbes to continue to propagate.
Meat processing generally includes a series of initial processing steps and then a number of final processing steps which result in the final meat products. In the initial processing steps, the animal is slaughtered, skinned, and cleaned to produce a whole carcass which is then usually cut into halves or sides. These whole or substantially whole carcasses are then cooled to an initial processing temperature and stored at that initial processing temperature for a period of time. After this initial refrigerated storage, the whole carcasses move on to the final processing steps in which the carcasses are cut down by butchering or trimming operations into the final products such as steaks, roasts, filets, and more finely comminuted products such as ground meat. Final processing may also include special processes that recover lean meat from trimmings left after conventional trimming operations.
In the initial processing, a carcass may be steamed in a steam cabinet and subjected to antibacterial washes while the carcass is still at or near slaughter temperature. This initial cleaning helps reduce the number of viable microbes on the carcass. The chilling or cooling is generally performed after these initial cleaning and antibacterial steps to take the carcass down from the slaughter temperature of approximately 100 degrees Fahrenheit to the initial storage temperature usually between 35 to 45 degrees Fahrenheit. This cooling is normally accomplished in two separate steps using two different chilling systems. In the first cooling step, the hot (slaughter temperature) carcass is placed in a first chiller commonly referred to as a “hot box” to begin the cooling process. After being cooled to some extent in the hot box, the carcass is transferred to a separate “holding cooler” for reducing the temperature of the carcass further and then holding the carcass within the desired temperature range for a period of time normally between 24 and 48 hours. From the holding cooler, the carcass is generally transferred to a location for final processing, either at the slaughter facility or at a separate final processing facility.
Hot boxes and holding coolers associated with initial meat processing operations commonly include a system for introducing a fine mist of chilled water into the enclosure. This water is added to the respective enclosure for the purpose of controlling shrinkage in the carcasses held in the enclosure. These misting systems generally include a supply of water, a chilling system for the water, and some arrangement for spraying the water into the enclosure in a fine mist.
Although the whole carcass may be subjected to processes immediately after slaughter to reduce microbe content on the carcass, these anti-microbial efforts inevitably leave viable microbes on the carcass for the initial cooling steps. The carcass itself may thus be a source of contamination for the hot box and holding cooler. A hot box, holding cooler, or other enclosure for meat products may also be contaminated with microbes introduced during service operations, with air-borne microbes, or with microbes introduced into the enclosure through the spray chilling system. The contaminating microbes may then spread throughout the enclosure and ultimately spread to previously uncontaminated meat products held in the enclosure. Thus, it is desirable to provide a method and apparatus for suppressing microbial activity or growth in the initial cooling enclosures and other enclosures in which meat may be held.
Prior hot box or holding cooler water misting systems have employed small quantities of chlorine in the water to help control microbial activity in the misting water and in the enclosure itself. Chlorinated misting water is disfavored, however, due to the detrimental effect of chlorine on the enclosure and associated equipment. Also, chlorinated misting water provides an antibacterial affect generally only on surfaces the mist reaches. Chlorinated misting water also may have a detrimental effect on the meat products stored in the enclosure. It is therefore desirable to provide an alternative and more effective method and system for suppressing microbial activity in enclosures used to hold meat products, especially coolers associated with initial meat processing operations.